Low back pain is considered to be one of the most widely experienced health problems in the U.S. and the world. Estimated costs to those who are severely disabled from low back pain range from $30-70 billion annually. Rates of spinal surgery in the US have increased sharply over time, and 12-fold geographic variation in rates of these surgeries has been documented. Despite these trends, there is little evidence establishing the efficacy and cost-effectiveness of surgical therapy versus non-operative management. The broad objective of the proposed research is to improve clinical decision making with respect to the surgical treatment of low back pain and associated leg symptoms in three major diagnostic groups: intervertebral disc herniation (IDH), spinal stenosis (SpS), and degenerative spondylolisthesis (DS). The Spine Patient Outcomes Research Trial (SPORT) has currently enrolled 2,317 patients with IDH, SpS and DS in three multi-center randomized controlled trials (RCTs) and associated observational cohorts to compare surgical to non-operative treatment for low back pain. By the end of the first funding cycle (November 2004), states. When completed, this will be largest and most methodologically sound study of the three most common diagnostic groups for which spine surgery is performed. SPORT II will extend the original follow-up for an additional five years. The primary endpoints will be long-term changes in health-related quality of life as measured by the SF-36 health status questionnaire and disease-specific disability as measured by the Oswestry Disability Index. Secondary long-term endpoints will include patient satisfaction with treatment, preference-weighted health outcomes to estimate quality-adjusted life years (QALYS), resource utilization and costs. SPORT II will provide insights into many methodological and clinical questions, including the generalizability of RCT results; patient preferences; disparity issues with respect to race, gender, and age; and geographic variability of clinical and economic outcomes. The RCT and observational cohorts will be integrated to estimate the cost-effectiveness of surgical vs. nonoperative interventions. Completion of SPORT II will provide, for the first time, both short and long term scientific evidence as to the relative efficacy/effectiveness of surgical versus non-surgical treatment for the three most commonly diagnosed lumbar spine conditions.